Abstract 4370619: When Bigger Isn’t Worse: The Obesity Paradox in Pulmonary Embolism — A Meta-Analysis

Background: Obesity is a well-established risk factor for venous thromboembolism, including pulmonary embolism (PE). Obese individuals are more likely to develop PE due to prothrombotic and inflammatory states associated with excess adiposity. However, an emerging body of evidence suggests that obese patients may experience unexpectedly favorable outcomes, a phenomenon known as the “obesity paradox.” This meta-analysis aimed to evaluate the impact of obesity on clinical outcomes in patients with pulmonary embolism (PE). Methods: A comprehensive literature search was conducted using PubMed, Embase, and Google Scholar databases. Random-effects models were used to calculate Mantel-Haenszel odds ratios (ORs) with 95% confidence intervals (CIs). Statistical significance was set at p < 0.05. Review Manager 5.0 (RevMan) was utilized for all statistical analyses. The primary endpoint was all-cause mortality from hospitalization till one-year follow-up. Secondary outcomes were major bleeding events in the same time frame. Obesity was defined as a body mass index (BMI) of 30 kg/m2 or greater, as per the World Health Organization (WHO) definition. Results: Seven studies, including 404,348 patients with pulmonary embolism (PE), were included in this analysis. Pooled data showed that obese patients had significantly lower all-cause mortality compared to non-obese patients (RR: 0.69; 95% CI: 0.64–0.74; p < 0.001), supporting the concept of a mortality paradox. Despite concerns that obesity might increase bleeding risk, no statistically significant difference in major bleeding events was observed between obese and non-obese groups (RR: 1.10; 95% CI: 0.70–1.72; p = 0.67). Conclusion: This meta-analysis demonstrates a clear mortality benefit in obese patients with PE without an increased risk of major bleeding, reinforcing the concept of an obesity paradox. Further research is needed to elucidate the underlying mechanisms and to guide risk-adapted management strategies in this population.